Modern Philosophy of Science has not yet recognized the significance of physical invariance principles for science and daily life. In this paper we investigate as a simple example, how time independence or time translational invariance of natural laws determines the time scale. We start with informal definitions of the invariance of concepts and laws. We then ask if time independence is an essential feature of natural laws or if time dependent laws are plausible without loss of predictive relevance. In section (...) 3 we investigate the question wether time independence of natural laws is a matter of convention. In sections 5-7 the determination of the time scale by time translational invariance is studied. In section 8 we study the conditions under which this determination is unique. (shrink)

Summary In the last decade analytical philosophy of science has been considered by many people as a descriptive activity. In part I of this paper we show that philosophy of science has been designed as normative logical analysis by Reichenbach and Carnap before world war II. Thus the identification analytical = descriptive is historically unjustified. In part II we discuss three tasks of analytical philosophy of science, the logical reconstruction of concepts, theories, and methods. While the first is mainly descriptive, (...) the third mainly normative, the second may be both, depending on the intended goal. (shrink)

The concept of necessity plays a central role in Kant's philosophy, but seems to lead to severe paradoxes. On the one hand he states: ‘Notwendigkeit und strenge Allgemeinheit sind sichere Kennzeichen einer Erkenntnis a priori’. On the other hand he talks also about ‘notwendig (d. i. nach einer Regel)’, which means ‘necessary according to the empirical natural laws’. However, he never states explicitly the distinction between these two different concepts of necessity. Either Kant's philosophy is inconsistent or we have to (...) assume that he indeed interchanges two different concepts, even if he does not tell us that there is a difference between synthetic apriori necessity and natural necessity. This paper defends the hypothesis of two different necessities and then shows how this strategy makes possible a rational reconstruction of Kant's epistemology. (shrink)

These arguments are fairly well known today. It is interesting to note that v. Kries already knew them, and that they have been ignored by Reichenbach and v. Mises in their original account of probability.2This observation leads to the interesting question why the frequency theory of probability has been adopted by many people in our century in spite of severe counterarguments. One may think of a change in scientific attitude, of a scientific revolution put forward by Feyerabendarian propaganda- and who (...) would deny that Reichenbach was an excellent propagandist!My suggested explanation is the following:J. v. Kries is still a mentalist in the tradition of Descartes and Locke. This can be shown very well from his logic, which he wrote even much later (1916). A mentalist does not pose semantical questions in a proper sense: he rather asks which ideas in the human mind make up a concept. And studying probability in this way, he will find in any case that what is in the human mind is first of all an expectation. Therefore, his analysis of the concept of probability will be centered around the concept of expectation.People tended to approach the problem in quite a different way after the scientific revolution which led from mentalism to lingualism. They tended in many cases to use operationalism and to ask how probabilities are determined in science, if they wanted to clear up the meaning of probability. This new aspect of probability, which was caused by looking at it from a new position or standpoint, suggested it to be the limit of relative frequencies in the first instance. This suggestion was so strong that all objections were ignored, and all counterarguments encountered deaf ears.Of course I have used here an oversimplification. Neither was J. v. Kries untouched by Poincaré's conventionalism, which is essentially a movement leading to the breakdown of mentalism; nor was Reichenbach, when he wrote his thesis in 1915, already a lingualist in any respect.Nevertheless, I think that the lingualist revolution, which took place particularly in mathematics and physics, has also changed the attitude towards probability. It would be interesting to corroborate this thesis by extensive study of the history of science in the late 19th century.Besides this historical aspect of v. Kries' theory, there is a systematic one which should be noticed. Though his theory still has a mentalist outlook, many of v. Kries' statements can be translated into the present lingualist idiom and then become most interesting contributions to the present discussion. We shall then state that for v. Kries probabilities appear first of all in probabilistic hypotheses which may or may not be confirmed by empirical data. Therefore, they have a role similar to theoretical concepts.3But that is not the only predominant feature of v. Kries' theory. He is approaching objective probability in a way which is quite unfamiliar to present day philosophers or mathematicians. Objective probabilities are connected with other concepts in three different ways. First of all, probabilistic hypotheses are confirmed by empirically found relative frequencies in a finite series of events. Secondly, they serve as an aid for decisions. And finally, there is a third relationship. Probabilities have to be explained by theories which are in many cases not formulated in probabilistic terms themselves. We can try to understand probability in one of the first two ways via their connection to other concepts. That is what is usually done by interpretations in terms of frequencies or decisions. A third approach, however, is to understand the nature of probability by the way probabilities are explained, and that is what v. Kries does. Such an approach does not seem unusual at all. In many cases the nature of a kind of objects is characterized by giving an explanation. If somebody asks what an eclipse of the moon is, we shall answer - as Aristotle already proposed - by giving an explanation of it. Thus it is quite natural to answer a question as to the nature of probability by describing the general type of explanation of probability distributions in natural or social science. The answer given by v. Kries is - as we know today — of limited validity. Quantum mechanical probabilities are not explainable by Spielräume. V. Kries solution, however, is remarkable in one important respect. It accounts for the time direction of objective probabilities, which are always predictive or forward probabilities, while retrodictive or backward probabilities are always subjective. The relation of objective probabilities to time direction is surely of utmost importance for natural philosophy. I do not know of any other philosophical foundation of probability which takes into account this deep-rooted relation. Therefore, v. Kries' interpretation may help us to understand one of the most intricate puzzles of philosophy. It may be nearly one hundred years old, but is by no means out of date. (shrink)

Hans Reichenbach's 1928 thesis of the relativity of geometry has been misunderstood as the statement that the geometrical structure of space can be described in different languages. In this interpretation the thesis becomes an instance of trivial semantical conventionalism, as Grünbaum calls it. To understand Reichenbach correctly, we have to interpret it in the light of the linguistic turn, the transition from thought oriented philosophy to language oriented philosophy, which mainly took place in the first decades of our century. Reichenbach (...) — as Poincaré before him — is undermining the prejudice of thought oriented philosophy, that two propositions have different factual content, if they are associated with different ideas in our mind. Thus Reichenbach prepared the change to language oriented philosophy, which he also accepted later. (shrink)

Summary Some leading ideas of the constructivist protophysics are discussed on the basis of P. Janich's Protophysik der Zeit. After having reviewed the contents of the second edition Janich's claim that analytical philosophy of science is purely affirmative and not critical towards science in its historical appearence is refuted. In the next section the principles of constructivist methodology of physics are criticised, and the claim is refuted that prescriptions for measurement cannot without circularity be shown to be invalid by experimental (...) results. In the last section we discuss Janich's foundation of time measurement in a mathematical frame similar to that for extensive systems. Thus the relation between Janich's and the ordinary account is cleared up. (shrink)

Some leading ideas of the constructivist protophysics are discussed on the basis of P. Janich's Protophysik der Zeit. After having reviewed the contents of the second edition Janich's claim that analytical philosophy of science is purely affirmative and not critical towards science in its historical appearence is refuted. In the next section the principles of constructivist methodology of physics are criticised, and the claim is refuted that prescriptions for measurement cannot without circularity be shown to be invalid by experimental results. (...) In the last section we discuss Janich's foundation of time measurement in a mathematical frame similar to that for extensive systems. Thus the relation between Janich's and the ordinary account is cleared up. (shrink)

Operational definitions were once considered the backbone of semantics of natural science. Still in 1955 A. W. Burks published an explication of the general scheme of these definitions. In the fifties of the last century however they became outmoded, while high school teachers for presumably good reasons were still in favour of them. I consider the banishment of this kind of definitions premature, and try to improve the explication of Burks in a way which qualifies them for a rehabilitation. In (...) the improved explication the concept of intrinsic property becomes important, for which I give a new definition on the basis of a structuralist account of physical processes. German Die operationalen Definitionen galten einst als der Kern der Semantik der Naturwissenschaft. Eine letzte Explikation des allgemeinen Schemas der operationalen Definitionen hat A. W. Burks noch 1955 vorgelegt. In den fünf ziger Jahren kamen sie indessen aus der Mode, während sie noch weiterhin von Gymnasiallehrern - wohl aus berechtigten Gründen - geschätzt wurden. Ich halte die Verbannung dieser Art von Definitionen für voreilig und versuche die Explikation von Burks in einer Weise zu verbessern, dass man sie wieder in der Wissenschaftstheorie rehabilitieren kann. In der verbesserten Explikation wird der Begriff der inneren Eigenschaft eines Dinges oder Vorgangs wichtig, den ich auf der Basis einer strukturalistischen Darstellung physikalischer Vorgänge neu definieren möchte. (shrink)

The determination of the meaning of theoretical terms by the axioms of theories as meaning postulates and the merely fictitious character of a basic observational language leads to Feyerabends problem of the incommensurability of physical theories. Different theories are actually compared by physicists as well. They might have a common sub-language as the language of macroscopic physics in atomic physics. Furthermore shared metalaws define an equivalence relation which identifies terms of different theories and enables physicists to talk about them in (...) a common language. (shrink)

The determination of the meaning of theoretical terms by the axioms of theories as meaning postulates and the merely fictitious character of a basic observational language leads to Feyerabends problem of the incommensurability of physical theories. Different theories are actually compared by physicists as well. They might have a common sublanguage as the language of macroscopic physics in atomic physics. Furthermore shared metalaws (e. g. invariance principles) define an equivalence relation which identifies terms of different theories and enables physicists to (...) talk about them in a common language. (shrink)

The aim of this paper is to discuss how far physics differs frommathematics, and if a philosophy of science which uses mathematics or logicsas a model for physics would be unable to be aware of many importantfeatures of that natural science.Many functions in physics differ from those of mathematics in beingfunctional dependecies and in having a lawlike character.Physical quantities have the character of "`determinables"'', sets ofspecial entities which are presupposed by physical theories.One may suspect that physics also could not be (...) formulated in anextensional language. This cannot be true, however, since every language canbe translated into an extensional version. Neverthless the existence ofdeterminables in physics shows that physics does not only talk aboutconcrete entities like space, time, spacetime, and particles, but also aboutvalues of abstract sets like determinables, and that it thus acknowledgestheir existence. (shrink)